Changeset 275097 in webkit

Timestamp:

Mar 26, 2021, 8:34:49 AM (5 years ago)

Author:

commit-queue@webkit.org

Message:

GraphicsContextGLOpenGL should avoid calling into ANGLE MakeCurrent
​https://bugs.webkit.org/show_bug.cgi?id=223511

Patch by Kimmo Kinnunen <​kkinnunen@apple.com> on 2021-03-26
Reviewed by Kenneth Russell.

Avoid calling ANGLE MakeCurrent for contexts that are already current. Cache the current context pointer into a
global variable. Currently the code adds no locking. For the forseeable future, ANGLE does not support
simultaneous access from multiple threads.

The optimization can be done when run in WebContent process or in GPU process, but not when in WK1. This is because in WK1,
the 3rd party client may run arbitrary code in WebKit thread. This includes code that changes EAGL or AGL state.
This code might change the current context underneath WebKit. In WK1 mode, we already use "volatile context" feature of
ANGLE to reset the platform context on every EGL command. The command we use for this for normal GL commands is EGL_MakeCurrent.
Makes in-process WebGL faster in MotionMark triangles by 6300 -> 9800 pts
Makes GPU process WebGL faster in MotionMark triangles by 5300 -> 7000 pts

• platform/graphics/cocoa/GraphicsContextGLOpenGLCocoa.mm:

(WebCore::isCurrentContextPredictable):
(WebCore::InitializeEGLDisplay):
(WebCore::GraphicsContextGLOpenGL::~GraphicsContextGLOpenGL):
(WebCore::GraphicsContextGLOpenGL::makeContextCurrent):
(WebCore::GraphicsContextGLOpenGL::clearCurrentContext):
(WebCore::GraphicsContextGLOpenGL::releaseCurrentContext):
(WebCore::GraphicsContextGLOpenGL::checkGPUStatus):

• platform/graphics/opengl/GraphicsContextGLOpenGL.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/cocoa/GraphicsContextGLOpenGLCocoa.mm (modified) (6 diffs)
• platform/graphics/opengl/GraphicsContextGLOpenGL.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-03-26  Kimmo Kinnunen  <kkinnunen@apple.com>
+
+        GraphicsContextGLOpenGL should avoid calling into ANGLE MakeCurrent
+        https://bugs.webkit.org/show_bug.cgi?id=223511
+
+        Reviewed by Kenneth Russell.
+
+        Avoid calling ANGLE MakeCurrent for contexts that are already current. Cache the current context pointer into a
+        global variable. Currently the code adds no locking. For the forseeable future, ANGLE does not support
+        simultaneous access from multiple threads.
+
+        The optimization can be done when run in WebContent process or in GPU process, but not when in WK1. This is because in WK1,
+        the 3rd party client may run arbitrary code in WebKit thread. This includes code that changes EAGL or AGL state.
+        This code might change the current context underneath WebKit. In WK1 mode, we already use "volatile context" feature of
+        ANGLE to reset the platform context on every EGL command. The command we use for this for normal GL commands is EGL_MakeCurrent.
+        Makes in-process WebGL faster in MotionMark triangles by 6300 -> 9800 pts
+        Makes GPU process WebGL faster in MotionMark triangles by 5300 -> 7000 pts
+
+        * platform/graphics/cocoa/GraphicsContextGLOpenGLCocoa.mm:
+        (WebCore::isCurrentContextPredictable):
+        (WebCore::InitializeEGLDisplay):
+        (WebCore::GraphicsContextGLOpenGL::~GraphicsContextGLOpenGL):
+        (WebCore::GraphicsContextGLOpenGL::makeContextCurrent):
+        (WebCore::GraphicsContextGLOpenGL::clearCurrentContext):
+        (WebCore::GraphicsContextGLOpenGL::releaseCurrentContext):
+        (WebCore::GraphicsContextGLOpenGL::checkGPUStatus):
+        * platform/graphics/opengl/GraphicsContextGLOpenGL.h:
+
 2021-03-25  Antoine Quint  <graouts@webkit.org>
 

trunk/Source/WebCore/platform/graphics/cocoa/GraphicsContextGLOpenGLCocoa.mm

@@ -50 +50 @@
 namespace WebCore {
 
+// In isCurrentContextPredictable() == true case this variable is accessed in single-threaded manner.
+// In isCurrentContextPredictable() == false case this variable is accessed from multiple threads but always sequentially
+// and it always contains nullptr and nullptr is always written to it.
+static GraphicsContextGLOpenGL* currentContext;
+
+static bool isCurrentContextPredictable()
+{
+    static bool value = isInWebProcess() || isInGPUProcess();
+    return value;
+}
+
 #if ASSERT_ENABLED
 // Returns true if we have volatile context extension for the particular API or
@@ -83 +94 @@
 
     // FIXME: This should come in from the GraphicsContextGLAttributes.
-    bool shouldInitializeWithVolatileContextSupport = !(isInWebProcess() || isInGPUProcess());
+    bool shouldInitializeWithVolatileContextSupport = !isCurrentContextPredictable();
     if (shouldInitializeWithVolatileContextSupport) {
         // For WK1 type APIs we need to set "volatile platform context" for specific
@@ -374 +385 @@
     }
     if (m_contextObj) {
-        EGL_MakeCurrent(m_displayObj, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+        clearCurrentContext();
         EGL_DestroyContext(m_displayObj, m_contextObj);
-    }
-
+    } else
+        ASSERT(currentContext != this);
     LOG(WebGL, "Destroyed a GraphicsContextGLOpenGL (%p).", this);
 }
@@ -428 +439 @@
     if (!m_displayBufferBacking && !getInternalFramebufferSize().isEmpty())
         return false;
-    // ANGLE has an early out for case where nothing changes. Calling MakeCurrent
-    // is important to set volatile platform context. See InitializeEGLDisplay().
+    if (currentContext == this)
+        return true;
+    // Calling MakeCurrent is important to set volatile platform context. See InitializeEGLDisplay().
     if (!EGL_MakeCurrent(m_displayObj, EGL_NO_SURFACE, EGL_NO_SURFACE, m_contextObj))
         return false;
+    if (isCurrentContextPredictable())
+        currentContext = this;
     return true;
+}
+
+void GraphicsContextGLOpenGL::clearCurrentContext()
+{
+    EGLBoolean result = EGL_MakeCurrent(m_displayObj, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+    ASSERT_UNUSED(result, result);
+    currentContext = nullptr;
 }
 
@@ -439 +460 @@
 {
     // At the moment this function is relevant only when web thread lock owns the GraphicsContextGLOpenGL current context.
-    ASSERT(!WebCore::isInWebProcess());
+    ASSERT(!isCurrentContextPredictable());
 
     if (!EGL_BindAPI(EGL_OPENGL_ES_API))
@@ -477 +498 @@
         m_failNextStatusCheck = false;
         forceContextLost();
-
-        EGL_BindAPI(EGL_OPENGL_ES_API);
-        EGL_MakeCurrent(m_displayObj, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+        clearCurrentContext();
         return;
     }

trunk/Source/WebCore/platform/graphics/opengl/GraphicsContextGLOpenGL.h

@@ -537 +537 @@
     // Called once by all the public entry points of ExtensionsGL that eventually call OpenGL.
     bool makeContextCurrent() WARN_UNUSED_RETURN;
+    void clearCurrentContext();
 
     // Take into account the user's requested context creation attributes,